The present invention relates to improvements in suppression of spray produced by wheeled vehicles moving upon highways, and particularly to a configuration for the surface of a spray-suppressant material for use behind and beside the wheels of a vehicle.
As a vehicle, for example a large truck, travels on a wet roadway surface, its wheels pick up liquids from the roadway surface. Such materials are thrown radially outwardly by the tires, forming spray. Such liquids may originate as rain water, slush from snow, melting ice, mud, and the like. When spray is thrown from vehicle tires against a solid surface on the vehicle it may be deflected or spattered into smaller droplets. As droplets rebound from solid surfaces on the vehicle they are likely to be caught in currents of turbulent air surrounding the vehicle. Such spray is carried in various directions, to be splashed against nearby vehicles, or to be suspended in the surrounding air as mist, producing annoying or dangerous conditions of poor visibility in the immediate vicinity of the vehicle.
Such splash and spray produced by a large moving vehicle is hazardous to other vehicles following or traveling alongside. It may impede the vision of the drivers of such other vehicles, or obscure the other vehicles from vision of the operator of the large vehicle causing the spray, leading to collisions between the vehicles.
With increasing numbers of vehicles present on the highways, and with highways having greater roadway width, the total amount of fluids likely to be present on the roadway surface and available to be thrown up into the air in the form of spray has increased. This makes the limitation of visibility by vehicle-produced spray an increasingly dangerous problem for drivers.
In order to reduce the amount of such splash and spray produced and thrown up in the way of other vehicles, large vehicles are required to have mud flaps hanging behind their wheels and to have spray-reducing side skirts in the vicinity of their wheels to collect and divert spray. Conventional mud flaps, however, have a relatively hard, generally planar front surface facing toward the wheels of a vehicle. Such a large planar surface generally merely deflects and splatters streams of impinging droplets thrown from the wheels of the vehicle, allowing most of such droplets and spray to continue to contribute to mist and spray in the turbulent air surrounding the vehicle.
An improved type of spray-reducing flap is disclosed in Reddaway U.S. Pat. No. 3,899,192, which teaches the provision of a plurality of elongate, resilient blade elements distributed over the surface of a flap. The blade elements project outwardly from the flap, extending generally toward the wheels of a vehicle in random, angular, crossing relationship to each other, to present a tangled mass of such blade elements for the purpose of absorbing and draining away fluid which strikes the flap.
Such a tangled mass of blade elements, however, has been found to retain mud, snow, and ice to an undesirable degree, and once appreciable amounts of mud or ice have been trapped in such a surface the flap has a much lower efficiency in limiting the amount of spray found in the vacinity of the wheels behind which such flaps are used.
A further improvement in spray-suppressent flaps is disclosed in Sullivan et al, U.S. patent application Ser. No. 526,436, filed Aug. 25, 1983, now U.S. Pat. No. 4,564,204. Such other publications as U.S. Pat. Nos. 4,382,606 and 4,398,739, U.K. Pat. No. 1,101,143 and U.K. pattent application Nos. 2 146 598A, 2 004 823B, 2 132 148A, and U.K. Design Registration No. 1,022,999 disclose other types of spray-reducing flap designs. However, greater spray suppression is still desired.
What is desired, then, is an improved spray-suppressant flap for use behind and alongside the wheels of a highway-operated vehicle to provide an improved amount of spray suppression at an economical cost. Preferably such a spray-suppressant flap should have an aesthetically pleasing appearance as well as the ability to entrap and divert downwardly a substantial part of the spray thrown against it from the wheels of a vehicle moving over a wet roadway.